Alkaline bright zinc electroplating

ABSTRACT

Bright zinc is electrodeposited from alkaline zinc electrodepositing baths comprising an alkaline solution containing a source of zinc ions and an effective amount, as a brightening agent, of a bath-soluble reaction product obtained by the reaction of a nitrogen-containing heterocyclic compound with an acyclic amine having at least two functional groups separated by at least one different group, formaldehyde, and an epihalohydrin or a glycerol chlorohydrin.

States Patent Kampe [151 3,655,534 [451 Apr. 11, 1972 [54] ALKALINEBRIGHT ZINC ELECTROPLATING [72] Inventor: Marcis M. Kampe, ClevelandHeights,

Ohio

Enthone, Incorporated, West Haven,

Conn.

[22] Filed: Feb. 24, 1970 [21] Appl.No.: 13,791

[73] Assignee:

[52] US. Cl. ..204/55, 204/DlG. 2 [51] Int. Cl. ..C23b 5/12, C23b 5/46[58] Field of Search ..204/55 R, 55 Y, 43, 44, 114;

2,680,712 6/1954 Diggin et a1 ..204/55 Y 3,227,638 1/1966 Burnson et a1...204/55 Y X Primary Examiner-G. L. Kaplan Attorney-Elwood J. Schafferand Roger J. Drew [5 7] ABSTRACT Bright zinc is electrodeposited fromalkaline zinc electrodepositing baths comprising an alkaline solutioncontaining a source of zinc ions and an effective amount, as abrightening agent, of a bath-soluble reaction product obtained by thereaction of a nitrogen-containing heterocyclic compound with an acyclicamine having at least two functional groups separated by at least onedifferent group, formaldehyde, and an epihalohydrin or a glycerolchlorohydrin.

26 Claims, No Drawings BACKGROUND or THE INVENTION 1. Field of theInvention This invention relates to alkaline zinc electrodepositing andmore particular to new alkaline bright zinc electrodepositing baths andto the electrodeposition of bright zinc therefrom. Additionally thisinvention isdirected to novel compositions and particularly compositionsespecially well suited .as' brightener additives for alkaline zincelectrodepositing baths.

'2. Description of the Prior Art Electrodeposition of zinc from alkalinecyanide zinc electroplatingbaths containing as a brightener additive areaction product of hexamethylenetetramine with epichlorohydrin oralpha-chlorglycerol is disclosed in the prior art. Bright zinc has alsobeen disclosedin the prior art as electrodeposited from cyanide zincelectroplating baths containing as brightener additive polyvinyl alcoholand a soluble reaction product of epichlorohydrin with ammonia or aprimary amine.

The electrodeposition of bright zinc froma cyanide-free a1 kaline bathcontaining an alkanolamine, hexamethylenetetramine, or a mixture thereofis also known to the prior art.

SUMMARY OF THE INVENTION In accordance with the present invention, 1have found that bright zinc can be electrodeposited from alkalinenon-cyanide and cyanide zinc electrodepositing baths comprising analkaline solution containing a source of zinc ions and an effectiveamount,'as a'brightening agent, of a bath-soluble'reaction productobtained by the reaction of a nitrogen-containing heterocyclic compoundwith an acyclic aliphatic primary amine containing two or morefunctional groups separated by one or more different groups or atoms,formaldehyde, and an epihalohydrin wherein the halogen atom is chloro orbromo or a glycerol chlorohydrin. The cyanide zinc electrodepositingbath can be a low cyanide content or a full or high cyanide contentbath. The reaction product brighteners of this invention attained in thezinc electrodeposits a considerably or a quinoline, wherein R ishydrogemmethyl, chloro, bromo, amino, cyano, vinyl, propanol or COOMwherein M is hydrogen or a hydrophilic cation, for example an alkalimetal, e.g. Na or K", cation, R, is hydrogen 'or amino with the provisothat when R is amino R is methyl, and R is hydrogen, methyl or -COOMwherein M is hydrogen or a hydrophilic cation, for example an'alkalimetal, e.g. Na or K, cation.

The acyclic amine'reactant for forming the soluble reaction productbrightener can be any acyclic aliphatic amine having two or morefunctional groups. Thus primary, secondary and tertiary amines areutilizable as the amine reactant so long as the amine has two or morefunctional groups. The two or more functional groups, for example ---OHand -Nl-l, groups, are separated by one or more different groups oratoms in the amine molecule. Exemplary ,of the amine reactant aremonoethanolamine, diethanolamine, triethylenetriamine,

.tetraethylenepentamine, triethanolamine, ethylenediamine anddiethylenetriamine. The functional groups in theamines enumeratedimmediately supra include the -NH OH, and NH groups. By functional groupas used herein in referring to the amine reactant having at least twofunctional under the reaction conditions of the invention. It isessential groups is meant a group or radical capable of reacting withanother reactant, group or radical in the reaction mixture, such as byan addition reaction'or a condensation reaction,

7 product brightener herein will usually be of the formula and theepihalohydrin or glycerol chlorohydrin, and a liquid diluent therefor.Usually the brightener additive of this invention comprises a solutionof such reaction product in a liquid aqueous solvent. I

- It is unnecessary to recover the reaction product of this inventionfrom the aqueous reaction product mixture, and the reaction product ofthis invention is utilizable as or in the brightener additivecomposition of this invention when in solution in the liquid diluent orsolvent of the reaction mixture or mass. Other constituents can be addedto the brightener additive composition, if desired, such as thebrighteners and other additives of the prior art hereinafter disclosed.

The reaction product brighter herein is added to the alkaline cyanideor.non-cyanide zinc electrodepositing baths herein in a minor amount,sufficient to impart brightness to the electrodeposited zinc.Thereaction product brightener is I cyclic or bicyclic heterocycliccompound and is usually of the 75 formulae Cr CHCH2X wherein X is chloroM15656. Such compounds include epichlorohydrin and epibromohydrin.

The glycerol chlorohydrin reactant will usually be of the formula:

I wherein at least one but not mTiETlTEn two Xs are hydroxy over widelimits. With lesser concentrations of the reaction product in thesolutions, more of the solution can be added to the zincelectrodepositing bath if required than when greater concentrations ofthe reaction product. As previously disclosed herein, such brighteneradditive composition is ordinarily the reaction product mixture or masstaken as such from the reactor, and without recovery of the reactionproduct from the mixture.

Brighteners and other additive agents well known in the prior art forcyanide zinc electroplating baths are utilizable in the non-cyanide andcyanide alkaline zinc electrodepositing baths herein together with thereaction product brightener of this invention. These prior artbrighteners and addition agents including agents for inhibiting voidformation and surface active agents can be added separately to the zinceleetrodepositing bath or may be added as a constituent of thecompositions of the present invention. When present in such additivecompositions of this invention, the prior art brightener or additive canbe present therein in any suitable amount. Such prior art brightencrsand addition agents include, for example, armatic aldehydcs, e.g.piperonal, anisic aldehyde, vanillin, salicylaldehydc, polyvinylalcohol, modified polyvinyl alcohol, e.g. oxidized polyvinyl alcohol,gelatin, polyether alcohols, polyesters, glue and peptone.

The reaction temperature for forming the soluble reaction productbrightener herein can be room temperature. Broadly the reactiontemperature can be from room temperature to reflux temperature of thereaction mixture inclusive. Higher temperature up to and includingreflux temperature speed up the reaction whereas lower temperatures androom temperature require longer reaction times for formation of thereaction product.

The proportions of the reactants are not especially critical and can bevaried over broad ranges.

The reaction time to yield the soluble reaction product brightener is,as is hereinbefore disclosed, dependent on the particular reactiontemperature employed with room temperature reacting requiringconsiderably longer times, as long as 12 hours, then elevatedtemperatures of 60 C. and up to reflux temperature which requiretypically about 1-2 hours to yield the reaction product brightener.

The reaction product brightener herein is light brown to dark brown incolor, and soluble in water and in the alkaline zinc electroplatingbaths herein. Under certain conditions, the reaction product herein mayhave a reddish coloration or tint in its brown color. When the reactionproduct is concentrated by expelling the water from the reaction productmass or mixture, the reaction product herein is a viscous semi-solid orsolid.

That the reactants have reacted to form the reaction product brightenerof this invention is evidenced by the evolution of heat by theexothermic reactions, a color change in the reaction mixture with thecolor thereof changing from a water white to a light brown to dark browncolor, and the fact the the epichlorohydrin, which is initiallyinsoluble in and suspended in the aqueous diluent, passes into solutionin the aqueous diluent after reacting.

The reactants can all be mixed together and reacted together in themixture, or they can be reacted together following a preferred sequenceof adding reactants to the reactor as is hereinafter disclosed.

The reactants herein are reacted together to form the reaction productbrightener in the presence of an aqueous liquid diluent, for examplewater, an aqueous solution of a l-3 C alkanol, e.g. methanol, ethanol orpropanol. When water is the diluent, which is usually the case, thewater includes that contributed by theformalin as well as thatcontributed by any aqueous solution of another reactant or reactants,for instance an aqueous solution of the primary amine, and also thewater formed by condensation reactions occurring. The amount of aqueousdiluent can be varied over a wide range and the amount of water in or asthe diluent is not especially critical except that when epichlorohydrinand monoethanolamine are reactants, an amount of water is utilized whichis sufficient to prevent the explosive reaction of the epichlorohydrinin the presence of the monoethanolamine. The water does not appear to bean inert diluent when an epihalohydrin, for instance epichlorohydrin isa reactant, inasmuch as it is believed that the water reacts with theepichlorohydrin to open up the epoxy ring to result in two hydroxylgroups in addition to the chlorine atom.

The source of zinc ions in the aqueous alkaline electrodepositing bathsherein can be zinc cyanide, Zn(CN) and/or an alkali metal zincate suchas sodium zincate, Na in0 or potassium zincate, K Zn O in the cyanidebaths, and

an alkali metal zincate such as sodium zincate or potassium zincate inthe non-cyanide baths herein. The cyanide and noncyanide alkaline bathsalso contain an alkaline material, usually an alkali metal hydroxide, egsodium or potassium hydroxide, with the zinc-containing compounddissolved in the aqueous alkaline solution. An alkali metal carbonate,e.g. sodium or potassium carbonate may also be a constituent of thecyanide and non-cyanide alkaline baths herein.

The electrodepositing of the bright or semi-bright zinc in accordancewith the invention is carried out by passing a DC electrical current,from an'anode or anodes through the alkaline non-cyanide or cyanide zincelectroplating bath solution containing the reaction product brightenerof this invention to a cathode or cathodes which is the article orarticles or objects on which the zinc is to be electrodeposited. Theelectrodepositing can be carried out at room temperature and attemperatures above room temperature up to about 50 C. Current densitiesof l-200 amps/sq. ft. are typically utilized. The anode or anodes may beconventional anodes well known in the art.

An aromatic amine of the formula IIIH:

wherein R is H, --NI-l or OH can also be a reactant herein for formingthe reaction product brightener when added together with gamma picolineas the nitrogen-containing heterocyclie compound reactant. Such aromaticamine of the formula immediately supra includes aniline andp-phenylenediamine. The other reactants, viz. the acyclic amine havingat least two functional groups, formaldehyde, and the 'epihalohydrin orglycerol halohydrin, are also reactants when such aromatic amine isutilized as a reactant together with the gamma picoline as reactant. Theratio of the aromatic amine of the formula supra to the gamma picolineas reactants is not especially critical and can be varied over a broadrange.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred amine having twoor more functional groups as reactant herein is monoethanolamine.

When an epihalohydrin, for instance epichlorohydrin is a reactant, theamount of water utilized in or as the aqueous diluent is preferably atleast equimolar with the epichlorohydrin, more preferably a moderate orlarge excess of water over such equimolar amount, for instance about 600percent excess of water over such equimolar amount.

Preferably the bath-soluble reaction product brightener herein isobtained or prepared by slowly adding an aqueous formaldehyde solutionof 37 percent formaldehyde concentration known as formalin to a mixtureof the amine having two or more functional groups, preferablymonoethanolamine, the nitrogen-containing heterocyclic compound, and theaqueous diluent while agitating the liquid mixture. Such slow or gradualaddition of the aqueous formaldehyde solution is usually over a periodof about 15 to about 30 minutes. Exothennic heat is liberated during theformaldehyde addition and it may or may not be necessary to cool thereaction mixture to about room temperature or slightly above roomtemperature prior to the addition of the epihalohydrin. If cooling isrequired prior to the epihalohydrin addition, the cooling may beeffected by indirect heat exchange of the reaction mixture with a fluidcoolant, for instance by cooling water circulating through the jacket ofa jacketted reactor, or, if desired, the cooling can be effected bysimply allowing the reaction mixture to cool to about room temperatureor slightly thereabove. The epihalohydrin, preferably epichlorohydrin isslowly added to the resulting liquid mixture, usually over a Thereactants are preferably reacted to form the reaction product brightenerin proportions within the molar ranges of about 0.5 1.5 mole of theamine having two of more functional groups, about 0.1 0.3 molenitrogen-containing heterocyclic compound, about 1.0 3.0 molesformaldehyde, and about 0.5 1.5 mole epihalohydrin or glycerolchlorohydrin.

The reaction product. brightener of this invention is preferably addedto the alkaline cyanide or non-cyanide zinc electrodepositing bathsherein in amount within the range of Zinc plating tests were separatelycarried out in alkaline non-cyanide, low cyanide and full or highcyanide content zinc electroplating baths to zinc-plate Hull testpanels. The plating was carried out in the Hull cell with the Hull cellpanel in each test run connected as cathode in the bath. The operatingconditions for the Hull cell were an operating current of 1-5 amps,usually 2 amps, room temperatureof the bath, and a plating time of 5minutes. A reaction product brightener of this invention prepared ashereafter disclosed and utilizing as the nitrogen-containingheterocyclic compound reactant for each test run thatnitrogen-containing heterocyclic compound specified in the Table lhereinafter set forth was added in amount of about 1 c.c. to an alkalinezinc'electroplating bath of one of the following compositions:

Non- Low High Cyanide Cyanide Cyanide Bath Bath Bath Zinc(oz./gal.) 0.984.7

Sodium hydroxide (oz./gal.) Water As indicated, certain of the bathswere non-cyanide, i.e. were free of cyanide; certain of the baths werelow cyanide baths containing 1 oz/gal. of sodium cyanide; and certain ofthe baths were full cyanide baths, i.e. high cyanide content baths,containing 12.7 oz/gal. of sodium cyanide.

The reaction product brightener was prepared by the following procedure:

Fifty (50) ml. water was added to a reaction vessel equipped with areflux condenser. 31.5 g. (approximately 0.5 mole) monoethanolarnine,and 6.0 g. (0.1 mole) isopropanol were added to the water in thereaction vessel. The mixture was stirred'and the particularnitrogen-containing heterocyclic compound in the amount specified inTable l hereinafter was added thereto. Sixty (60.0) .g. (approximately0.75 mole) aqueous 37 percent formaldehyde was then added to the mixturein the reaction vessel while stirring the mixture, and the reactionmixture cooled to near room temperature. Forty-six (46.0.) g. (0.5 mole)epichlorohydrin was then slowly added to the mixture in the reactionvessel with stirring of the mixture ,during such addition. Theepichlorohydrin was added to-the mixture over an approximately 60 minuteperiod. The resulting reaction mixture was then refluxed for k hour,cooled and stored in a container.

In the Table l of test results which follows, H cd" means a high currentdensity of 40-100 amplft M ed" means a middle current density of 20amp/ft up to amp/ft; and L ed" means a low current density of slightlyabove 0 and up to 20 1 amp/ft? Also in the following Table l, L-l-l cdmeans in the low, middle and high current density ranges as set forthimmediately above, H-M ed means in the high and middle c ur TAB LE IAmount of nitrogen containing heterocyclic compound Test Run Particularnitrogen containing hetcrocyreactant utilized, mole/0.5 Non-cyanide zincLow-cyanide zinc High cyanide zinc Number clic compound reactant ml. ofepichlorohydrin plating bath plating bath plating bath 1 Alpha-plcoline0.1 mole Br, H cd F, Br, L-H cd F, Br, 1,11 ed.

. F, Br, H-M ed F; Br, L-H ed F, Br, L-H ed. Br, H-M cd Br, M cd F, Br,M-L ed. Br, H-M cd 13, Br, L-H cd F, (1131, L and H 5 Beta-picoline 0.1mole F, Br, L ed F, Br, H-L ed F, Br, M-L cd I CH;

6 Gamma-picollne 0.1 mole V, Br, H-M cd Br, H-M cd Br, M ed \NJ ,7 v

7 Gamma-picolino and aniline. 0.1 mole and 0.1 mole F, Br, M-L ed F, Br,L-H cd F, Br, M ed.

Table 1 Cominued Amount of nitrogen containing heterocyclic compoundTest Run Particular nitrogen containing heterocyreactant utilized,mole/0.6 Non-cyanlde zinc Low-cyanide zinc High cyanide zinc Numbor cliccompound reactant m1. of eplchlorohydnn plating bath plating bathplutlngbnth 8 lsoqu o ne ole V, Br, M ed Br, 11-1, cd Br, n.

Same as above -05 mole Br, H-L ed Br, H-L ed F, Br, M-L cd.

Plcolinlc acid -1 mole Dull, H-L ed F, Br, H-L cd F, Br, M-L cd.

C 0 O H J* 11 Isonicotlnlc acid -1 mole Dull, H-L cd F, Br, H-L cd F,Br, H-L ed C 0 O H Q 12 Nlcotinic acli 0.1 mole Br, H-L ed Br, H-L cd V,Br, H-L cd (To 0 OH N r V .V

13 Condensation reaction product of mono- Does not apply F, Br, L edDull, 3. ed n, ed

ethanol-amino, Iormaldchydo and cplchlorohydrin.

14 Pyridine 111016 Dull, H-L cd F, Br, HL cd F, Br, H-L ed 15 py d e v,Br, H-M cd Br, M-L cd Br, M-L ed HC=CII2 16 4-cyanopyridine -1 moleDull, H-L cd F, Br, H-L cd F, Br, H-L cd CN J 17 Hhloropyridlne -1 moleF, Br, M-L cd F, Br, H-L ed F, Br, M-L cd 18 4-propanolpyridinc -1 moleBr, H-L cd Br, H-L ed Br, H-L cd CH2-CH2-CII2-CH N 7 7M, 7 r W W V V n,r

19 Ggrlnmii-picoline and para-phenylene- 0.1 mole and 0.05 mole V, Br, Med V, Br, H-M cd Br, M ed am no CH3 and N H2 Table l Continued Amount ofnitrogen containing heterocyclic compound Test Run Partlcular mtrogencontaining heterocyreactant utilized, mole/0.5 Non-cyanide zincLow-cyanide zinc High cyanide zinc Number clio compound reactant ml. ofepichlorohydrin plating bath plating bath plating bath 2o -L- Same above0.08 mole and 0.0255016 v, Br, M ed Br, H-L cd Br, M-L ed 21Ganma-picoline and Z-methylpyraz- 0.08 mole and 0.07 mole V, Br, M ed F,Br, H cd I Br, H-M ed (His and N l N CH: N

22 4-plcolylamina 0.1 mole Br, M ed Br, M-L cd Br, H-M cd 7 NH: @CHa N23 2,4,6collidino 0.1 mole Dull; H-L cd Dull, H-L ed Dull, H-L ed CH3 IHaC J-OH: N

24 2-methylpy'razine 0.1 mole 5. Br, 11-1. cd Br, H-L ed F, Br, H-L ed Nk CH3 25 2-pyrazinecarboxylic acid 0.1 mole Dull, H-L ed F, Br, H-L cdF, Br, H-L cd N C O O H The good results in brightness of theelectrodeposited zinc obtained utilizing thereactionproductbrightenersof this invention in the zinc electrodepositingbaths is-shown by the.test results of Table l. I

' Additional zinc platingtests were carried. out'to evaluatevariousreaction products asxbrightener additivesto non-cya-. nide, low cyanide,and, full or high cyanide zinc electroplating baths. Test Runs No.-s26-38 whichfollow are concerned with electroplating of zinc fromnon-cyanide, i.e. cyanide-free, alkaline zinc electrodepositing baths,Test Runs No.s 39-55 which follow relate to electroplating of zinc fromlow cyanide content alkaline zinc electrodepositing baths, and Test RunsNo.s 56-67 also which follow are concerned with electroplating of zincfrom .full. cyanide, i.e. high cyanidecontenu'alkaline zincelectrodepositing baths.

The reactionproduct brightener for thezinc electrodepositing baths ofTest Runs No.s 26-67 hereafter set forth was prepared by combiningwithwater 0.5 mole of the particular amine having two or more functionalgroups and .0.1 mole isopropanol. When a nitrogen-containingheterocyclic compound was a reactant, 0.1 mole of nicotinic acid or 0. 1mole of gamma picoline was mixed together with the aqueous mixture 5 ofthe amine and isopropariol. 0.75 mole formaldehyde in aqueous solutionof 37 percent. formaldehyde concentration was then stirred into thethus-obtained-mixture, and the resulting mixture allowed to cool to roomtemperature.

Epichlorohydrin in the amount of 0.5 mole, or-0.5 mole of Reactionproduct of die'thanolamine; formal- Esters?9 eia i ygbey t ebeat829%.

TEST RUN NO. 27

Reaction product of diethanolamine, aqueous forrnaldehyde of 37 percentformaldehyde concentration, epichlorohydrin andnicotinic acid, in amountof l V: ml., was addedto an alkaline non-cyanide zinc electroplatingbath of the same composition as in Test Run No. 26 in a 267 ml. Hulltest cell.

The zinc electrodeposit on the Hull test panel was semibright in therange of about 4-37 amps/ft and bright in the range of slightly above 0up to about 4 amps/ft? TEST RUN NO. 28

Reaction product of diethanolamine, aqueous formaldehyde of 37 percentformaldehyde concentration, epichlorohydrin and 'y-picoline, in amountof 1 ml., was added to an alkaline non-cyanide zinc electroplating bathof the same composition as in Test Run No. 26 in a 267 ml. Hull testcell.

The zinc electrodeposit on the Hull test panel .was semibright in therange of about 55-85 amps/ft.

11 TEST RUN NO. 29

Reaction product of triethanolamine, aqueous formaldehyde of 37 percentformaldehyde concentration and epichlorohydrin, in amount of l /2 ml.,was added to an alkaline non-cyanide zinc electroplating bath of thesame composition as in Test Run No. 26 in a 267 ml. Hull test cell.

The zinc electrodeposit on the Hull test panel was semibright in therange of slightly above up to about 4 amps/ft? TEST RUN NO. 30

Reaction product of triethanolamine, aqueous formaldehyde of 37 percentformaldehyde concentration, epichlorohydrin and y-picoline, in amount of1 A ml., was added to an alkaline non-cyanide zinc electroplating bathof the same composition as in Test Run No. 26 in a 267 ml. Hull testcell.

The zinc electrodeposit on the Hull test panel was bright in the rangeof about 14l00 amps/ft? TEST RUN NO. 31

Reaction product of hexamethylenetetramine, aqueous formaldehyde of 37percent formaldehyde concentration, epichlorohydrin and nicotinic acid,in amount of 1 V. ml., was added to an alkaline, aqueous non-cyanidezinc electroplating bath containing 0.99 oz./gal. Zn and 9.4 oz./gal.NaOH in a 267 ml. Hull test cell.

The zinc electrodeposit on the Hull test panel was bright in the rangeof slightly above 0 to 100 amps/ft.

TEST RUN NO. 32

Reaction product of hexamethylenetetramine, aqueous formaldehyde of 37percent formaldehyde concentration, epichlorohydrin and 'y-picoline, inamount of 1 /2 ml., was added to an alkaline, aqueous non-cyanide zincelectroplating bath containing 0.99 oz./gal. Zn and 9.4 oz./gal. NaOH ina 267 ml. Hull test cell.

The zinc electrodeposit on the Hull test panel was bright in the rangeof slightly above 0 to 98 amps/ft? TEST RUN NO. 33

Reaction product of ethylenediamine, aqueous formaldehyde of 37 percentformaldehyde concentration, epichlorohydrin and nicotinic acid, inamount of 541 ml., was added to an alkaline, aqueous non-cyanide zincelectroplating bath containing 0.99 oz./gal. Zn and 9.4 oz./gal. NaOH ina 267 ml. Hull test cell. 7

The zinc electrodeposit on the Hull test panel was semibright in therange of slightly above 0 to about 62 amps/ft? TEST RUN NO. 34

Reaction product of ethylenediamine, aqueous formaldehyde of 37 percentformaldehyde concentration, epichlorohydrin and y-picoline, in amount ofV1 ml., was added to an alkaline, aqueous non-cyanide zincelectroplating bath containing 0.99 oz./gal. Zn and 9.4 oz./gal. NaOH ina 267 ml. Hull test cell.

The zinc electrodeposit on the Hull test panel was bright in the rangeof slightly above 0 to about 60 amps/ft.

TEST RUN NO. 35

Reaction product of monoethanolamine, aqueous formaldehyde of 37 percentformaldehyde concentration, and glycerol dichlorohydrin, in amount of 1%ml., was added to an alkaline, aqueous non-cyanide zinc electroplatingbath containing 0.99 oz./gal. Zn and 9.4 oz./gal. NaOH in a 267 ml. Hulltest cell.

The zinc electrodeposit on the Hull test panel was dull in the range offrom 0 to about ampslft and was a burnt, dark deposit in the range ofabout 20 to 100 amps/ft.

1 TEST RUN NO. 36

Reaction product of monoethanolamine, aqueous formaldehyde of 37 percentformaldehyde concentration, glycerol dichlorohydrin and 'y-picoline, inamount of 1% ml., was added to an alkaline, aqueous non-cyanide zincelectroplating bath containing 0.99 oz./gal. Zn and 9.4 oz./gal. NaOH ina 267 ml. Hull test cell. i

The zinc electrodeposit on the Hull test panel was semibright in therange of about 12 to about 40 amps/ft? TEST RUN NO. 37

Reaction product of ethylenediamine, aqueous formaldehyde of 37 percentformaldehyde concentration, and glycerol monochlorohydrin, in amount of1 /2 ml., was added to an alkaline, aqueous non-cyanide zincelectroplating bath containing 0.99 oz./gal. Zn and 9.4 oz./gal. NaOH ina 267 ml. Hull test cell.

The zinc electrodeposit on the Hull test panel was dull in the range of0 to about 35 ampslft and a burnt, dark deposit in the range of about 35to amps/ft TEST RUN NO. 38

Reaction product of ethylenediamine, aqueous formaldehyde of 37 percentformaldehyde concentration, glycerol monochlorohydrin, and nicotinicacid in amount of 1% ml., was added to an alkaline, aqueous non-cyanidezinc electroplating bath containing 0.99 oz./gal. Zn and 9.4 oz./gal.NaOH in a 267 ml. Hull test cell.

The zinc electrodeposit on the Hull test panel was bright in the rangeof about 10 to about 48 amps/ft That the reaction product brightener ofthe present invention considerably enhanced the brightening effect, therange of brightness, or both of the zinc electrodeposited from thecyanide-free zinc plating bath is shown by Test Runs N0. 27, 28, 3034,36 and 38 wherein the plating baths contained the reaction productbrightener of the invention as compared with Test Runs 26, 29, 35 and 37wherein the baths contained as additive a reaction product not of thepresent invention.

TEST RUN NO. 39

TEST RUN NO. 40 7 Reaction product of diethanolamine, aqueousformaldehyde of 37 percent formaldehyde concentration, epichlorohydrinand nicotinic acid, in amount of 1 A2 ml., was added to the alkaline lowcyanide zinc electroplating bath of the same composition as in Test RunNo. 39 in a 267 ml. Hull test cell.

The zinc electrodeposit on the Hull test panel was bright over theentire range of slightly above 0 to 100 amps/ft? TEST RUN NO. 41

Reaction product of diethanolamine, aqueous formaldehyde of 37 percentformaldehyde concentration,

epichlorohydrin and 'y-picoline, in amount of V4 ml., was added to analkaline, low cyanide zinc electroplating bath of the same compositionas in Test Run No. 39 in a 267 ml. l-lull test cell.

The zinc electrodeposit on the Hull test panel was bright over theentire range of slightly above 0 to 100 amps/ft? TEST RUN NO. 43

Reaction product of triethanolamine, aqueous formaldehyde of 37 percentformaldehyde concentration, epichlorohydrin and nicotinic acid, inamount of l 7% ml., was added to an alkaline, aqueous non-cyanide zincelectroplating bath of the same composition as in Test Run No. 39 in a267 ml. l-lull test cell.

The zinc electrodeposit on the Hull test panel was bright in the rangeof about 10-90 amps/ft? TEST RUN NO. 44

Reaction product of hexamethylenetetramine, aqueous formaldehyde of 37percent formaldehyde concentration, epichlorohydrin and nicotinic acid,in amount of A ml., was added to the alkaline low cyanide zincelectroplating bath of the same composition as in Test Run No. 39 in a267 ml. l-lull Test cell.

The zinc electrodeposit on the Hull test panel'was bright over the rangeof slightly above 0 to 100 ampslft TEST RUN NO. 45

Reaction product of hexamethylenetetramine, aqueous formaldehyde of 37percent formaldehyde concentration,

epichlorohydrin and 'y-picoline, in amount of A ml., was

added to the alkaline low cyanide zinc electroplating bath of the samecomposition as in Test Run No. 39 in a 267 ml. Hull Test cell. i

The zinc electrodeposit on the Hull test panel was bright over theentire range of slightly above 0 to .100 amps/ft.

TEST RUN NO. 46

Reaction product of ethylenediamine, aqueous formaldehyde of 37 percentformaldehyde concentration and epichlorohydrin, in amount of ml., wasadded to the alkaline low cyanide zinc electroplating bath of the samecomposition as in Test Run No. 39 in a 267 ml. Hull Test cell.

The zinc electrodeposit on the Hull test panel was semibright over therange of slightly above 0 to 100 amps/ft TEST RUN NO. 47

Reaction product of ethylenediamine, aqueous formaldehyde of 37 percentformaldehyde concentration, epichlorohydrin and nicotinic acid, inamount of A ml., was added to the alkaline low cyanide zincelectroplating bath of the same composition asin Test Run No. 39 in a267 ml. Hull Test cell.

The zinc electrodeposit on the Hull test panel was bright in the rangeof about 20-100 amps/ft? TEST RUN NO. 48

Reaction product of triallylamine, aqueous formaldehyde of 37 percentformaldehyde concentration and epichlorohydrin, in amount of A ml., wasadded to the alkaline low cyanide zinc electroplating bath ofthe samecomposition as in Test Run No. 39in a 267 ml. Hull Test cell.

The zinc electrodeposit on the Hull test panel was cloudy over theentire range of slightly above 0 to 100 amps/ft? TEST RUN NO. 49

Reaction product of triallylamine, aqueous formaldehyde of 37 percentformaldehyde concentration, epichlorohydrin and 'y-picoline, in amountof a added 'm' the alkaline low cyanide zinc electroplating bath of thesame composition as in Test Run No. 39 in a 267 ml. Hull Test cell.

r The zinc electrodeposit on the Hull test panel was bright in the rangeof about 2-40 amps/ft.

TEST RUN NO. 50

Reaction product of diethylenetriamine, aqueous femaldehyde of 37percent formaldehyde concentration and epichlorohydrin, in amount of 14ml., was added to'the alkaline low cyanide zinc electroplating bath ofthe same composition as in Test Run No. 39 in a 267 ml. Hull Test cell.

The zinc electrodeposit on the Hull test panel was dull in the range ofabout 5-94 amps/ft, and semi-bright in the range of about 94-100amps/ft".

TEST RUN NO. 51

Reaction product of diethylenetriamine, aqueous forrnaldehyde of 37percent formaldehyde concentration, epichlorohydrin and nicotinic acid,in amount of A ml., was added to the alkaline low cyanide zincelectroplating bath of the same composition as in Test Run 39 in a 267ml. Hull Test cell.

The zinc electrodeposit on the Hull test panel was semibright in therange of about 36-87 amps/ft, and bright in the range of about 87-100amps/ft? TEST RUN NO. 52

Reaction product of monoethanolamine, aqueous formaldehyde of 37 percentformaldehyde concentration, glycerol dichlorohydrin and nicotinic acid,in amount of 1 V2 ml., was added to the alkaline low cyanide zincelectroplating bath of the same composition as in Test Run No. 39 in a267 ml. l-lull Test cell.

The zinc electrodeposit on the Hull test panel was bright over theentire range of slightly above 0 to amps/ftf".

TEST RUN NO. 53

TEST RUN NO. 54

Reaction product of monoethanolamine, aqueous formaldehyde of 37 percentformaldehyde concentration, glycerol monochlorohydrin, and 'y-picoline,in amount of 1 ml., was added to the alkaline low cyanide zincelectroplating bath of the same composition as in Test Run No. 39 in a267 ml. Hull test cell.

The zinc electrodeposit on the Hull test panel was bright in the rangeof about 8 to 100 amps/ft TEST RUN NO. 55

Reaction product of ethylene diamine, aqueous formaldehyde of 37 percentformaldehyde concentration, glycerol monochlorohydrin, and nicotinicacid, in amount of l 9% ml., was added to the alkaline low cyanide zincelectroplating bath of the same composition as in Test Run No. 39 in a267 ml. Hull test cell.

The zinc electrodeposit on the Hull test panel was bright in the rangeof about 6 to about 93 amps/ft A comparison of the zinc deposits fromthe low cyanide plating baths of Test Run No.s 40, 41, 43-45, 47, 49 and51-55 containing a reaction product brightener of the invention with thezinc deposits from the low cyanide baths of Test Run No.s 39, 42, 46, 48and 50 containing asadditive a reaction product not of the presentinvention, evidences the considerable increase in brightening effect,range of brightness, or both provided by the reaction productbrighteners of the present invention.

TEST RUN NO. 56

Reaction product of diethanolamine, aqueous formaldehyde of 37 percentformaldehyde concentration, epichlorohydrin and nicotinic acid, inamount of /2 ml., was added to an alkaline aqueous full or high cyanidezinc electroplating bath containing 4.5 oz./gal. Zn, 10.3 oz./gal. NaOHand 13.4 oz./gal. NaCN in a 267 ml. Hull test cell.

The zinc electrodeposit on the Hull test panel was bright over theentire range of slightly above 0 to 100 amps/ft? TEST RUN NO. 57

TEST RUN NO. 58

Reaction product of triethanolamine, aqueous formaldehyde of 37 percentformaldehyde concentration, and

epichlorohydrin, in amount of 1 ml., was added to an alkaline aqueousfull or high cyanide zinc electroplating bath containing 4.5 oz./gal.Zn, 10.3 oz./gal. NaOH and 13.4 oz./gal. NaOH and 13.4 oz./gal. NaCN ina 267 ml. Hull test cell.

The zinc electrodeposit on the Hull test panel was cloudy in the rangeof slightly above 0 to about 7 amps/ft and bright in the range of about7-100 amps/ft.

TEST RUN NO. 59

Reaction product of hexamethylenetetramine, aqueous formaldehyde of 37percent formaldehyde concentration, epichlorohydrin and nicotinic acid,in amount of /2 ml., was added to an alkaline aqueous full or highcyanide zinc electroplating bath containing 4.5 oz./gal. Zn, 10.3o2./gal. NaOH and 13.4 oz./gal. NaCN in a 267 ml. Hull test cell.

The zinc electrodeposit on the Hull test panel was bright over theentire range of slightly above 0 to 100 amps/ft TEST RUN NO. 60

Reaction product of hexamethylenetetramine, aqueous formaldehyde of 37percent formaldehyde concentration, epichlorohydrin and y-picoline, inamount of 5 4 ml., was added to an alkaline aqueous full or high cyanidezinc electroplating bath containing 4.5 oz./gal. Zn, 10.3 oz./gal. NaOHand 13.4 oz./gal. NaCN in a 267 ml. Hull test cell.

The zinc electrodeposit on the Hull test panel was bright over theentire range of slightly above 0 to 100 amps. ft although a cloud waspresent in the deposit.

TEST RUN NO. 61

Reaction product of ethylene diamine, aqueous formaldehyde of 37 percentformaldehyde concentration, epichlorohydrin and nicotinic acid, inamount of V1 ml., was added to an alkaline aqueous full or high cyanidezinc electroplating bath containing 4.5 oz./gal Zn, 10.3 oZ./gal. NaOHand 13.4 oz./gal. NaCN in a 267 ml. Hull test cell.

The zinc electrodeposit on the Hull test panel was bright over theentire range from slightly above 0 to 100 amps/ft".

TEST RUN NO. 62

Reaction product of ethylenediamine, aqueous formaldehyde of 37 percentformaldehyde concentration, epichlorohydrin and 'y-picoline, in amountof A ml., was added to an alkaline aqueous full or high cyanide zincelectroplating bath containing 4.5 oz./gal. Zn, 10.3 oz./gal. NaOH and13.4 oz./gal. NaCN in a 267 ml. Hull test cell.

The zinc electrodeposit on the Hull test panel was bright over theentire range of slightly above 0 to amps/ft.

TEST RUN NO. 63

Reaction product of monoethanolamine, aqueous formaldehyde of 37 percentformaldehyde concentration, glycerol dichlorohydrin and nicotinic acid,in amount of l k ml., was added to an alkaline aqueous full or highcyanide zinc electroplating bath containing 4.5 oz./gal Zn, 10.3oz./gal. NaOH and 13.4 oz./gal. NaCN in a 267 ml. l-lull test cell.

The zinc electrodeposit on the Hull test panel was bright over theentire range of slightly above 0 to 100 amps/ft.

TEST RUN NO. 64

Reaction product of monoethanolamine, aqueous formaldehyde of 37 percentformaldehyde concentration, glycerol dichlorohydrin and y-picoline, inamount of 1 9% ml., was added to an alkaline aqueous full or highcyanide zinc electroplating bath containing 4.5 oz./gal. Zn, 10.3oz./gal. NaOH and 13.4 oz./gal. NaCN in a 267 ml. Hull test cell.

The zinc electrodeposit on the Hull test panel was bright over theentire range ofslightly above 0 to 100 amps/ft.

TEST RUN NO. 65

Reaction product of monoethanolamine, aqueous formaldehyde of 37 percentformaldehyde concentration, glycerol monochlorohydrin, and nicotinicacid, in amount of A ml., was added to an alkaline aqueous full or highcyanide zinc electroplating bath containing 4.5 oz./gal. Zn. 10.3oz./gal. NaOH and 13.4 oz./gal. NaCN in a 267 ml. Hull test cell.

The zinc electrodeposit on the Hull test panel was bright over theentire range of slightly above 0 to 100 amps/ft.

TEST RUN NO. 66

Reaction product of monoethanolamine, aqueous formaldehyde of 37 percentformaldehyde concentration, glycerol monochlorohydrin, and 'y-picoline,in amount of A ml., 'was added to an alkaline aqueous full or highcyanide zinc electroplating bath containing 4.5 oz./gal. Zn, 10.3oz./gal. NaOH and 13.4 oz./gal. NaCN in a 267 ml. Hull test cell.

The zinc electrodeposit on the Hull test panel was bright over theentire range of slightly above 0 to 100 amps/ft? TEST RUN NO. 67

Reaction product of diethanolamine, aqueous formaldehyde of 37 percentformaldehyde concentration, and epichlorohydrin, in amount of k ml., wasadded to an alkaline aqueous full or high cyanide zinc electroplatingbath containing 4.5 oz./gal Zn, 10.3 oz./gal. NaOH and 13.4 oz./gal.NaCN in a 267 ml. Hull test cell.

The zinc electrodeposit on the Hull test panel was cloudy in the rangeof from slightly above 0 to about 4 amps/ft and bright in the range ofabout 4 to 100 amps/ft.

The Test Runs No. s 56, 57, 59-66 show the good brightness and widerange of brightness provided by full cyanide, i.e. high cyanide content,alkaline zinc electrodepositing baths containing reaction productbrighteners of the invention. The zinc deposits provided by the fullcyanide zinc electrodepositing baths of Test Runs No. 58 and 67containing as additive a reaction product not of this invention werebright over a narrower range than were zinc deposits from full cyanideelectrodepositing baths containing reaction product brighteners of thepresent invention.

The term low cyanide" content used herein with reference to the alkalinezinc cyanide electrodepositing bath means such, a bath with a totalcyanide content of up to 2.0 oz./gal. The terms full cyanide content orhigh cyanide content used herein in referring to the alkaline zincelectrodepositing bath means such a bath with a total cyanide content of10.0 oz./gal. or higher.

What is claimed is:

1. An aqueous alkaline zinc electrodepositing bath comprising an aqueousalkaline solution containing a source of zinc ions and an effectiveamount, sufficient to yield a bright zinc electrodeposit, of abath-soluble reaction product obtained by the reaction of a nitrogenheterocyclic compound with an acyclic amine having at leasttwo-functional groups, formaldehyde, and an epihalohydrin wherein thehalogen is chloro or bromo or a glycerol chlorohydrin at a reactiontemperatureof from room temperature to reflux temperature inclusive.

ZQThe bath of claim 1 wherein'the bath is a low cyanide content bathhaving a total cyanide content of up to 2.0' oz./gal and wherein thenitrogen heterocyclic compound is of the formula I tion product, saidadditional reactant being an aromatic amine of the formula wherein R is-H, NH or[OH.

6. The'bath of claimS wherein the R is Nl-l 7. The bath of claim 2wherein the nitrogen heterocyclic 13. The bath of claim 12 wherein theepihalohydrin is epichlorohydrin and the bath-soluble reaction productis obtained by slowly adding an aqueous formaldehyde solution to amixture of the amine having at least two functional groups, the nitrogenheterocyclic compound and an-aqueous diluent while agitating themixture, slowly adding the epichlorohydrin to the thus-obtained mixturewhile agitating the mixture whereby exothermic heat is liberated duringthe epichlorohydrin addition with an attendant rise in temperature ofthe mixture to about its reflux temperature, and refluxing the resultingmixture for a period of at least about 20 16. The bath of claim 1wherein the bath is free of cyanide,

the quinoline is isoquinthe nitrogen heterocyclic compound reactant isselected from the groups consisting of 01-, [3- and -y-picolines,nicotinic acid, vmylpyrrdmes, halopyridines wherein the halogen ischloro or bromo, picolylamines, methylpyrazines and quinolines; and

the amine reactant having at least two functional groups is selectedfrom the groups consisting of mono-, diand triethanolamine,hexamethylenediamine, hexamethylenetetramine, ethylenediamine,diethylenetriamine and tetraethylenepentamine.

17. The non-cyanide bath of claim 16 wherein the nitrogen heterocycliccompound is selected from the group consisting of 'y-picoline, nicotinicacid, 4-vinylpyridine, 2- chloropyridine, 4-picolylamine,2-methylpyrazine and isoquinoline.

18. The bath of claim 1 wherein the nitrogen heterocyclic compound isZ-methyl pyrazine.

19. The bath of claim 1 wherein the nitrogen heterocyclic compoundis'y-picoline and 2-methylpyri'zine.

20. An aqueous alkaline zinc electrodepositing bath comprising anaqueous alkaline solution containing a source of zinc ions and anefiective amount, sufficient to yield a bright .zinc electrodeposit, ofa bath-soluble reaction product obtained by the reaction of a nitrogenheterocyclic compound selected from the group consisting of those of theformulae:

and a quinoline, wherein R is hydrogen, methyl, chloro, bromo, amino,cyano, vinyl, hydroxypropyl or COOM wherein M is hydrogen or ahydrophilic cation, R, is hydrogen or amino with the proviso that whenR, is amino R is methyl, and R is hydrogen, methyl or COOM wherein M ishydrogen or a hydrophilic cation with an acyclic amine having at leasttwo functional groups, formaldehyde, and an epihalohydrin of the formulawherein X is chloro or bromo or a glycerol chlorohydrin of the formulaCH2(l3H-(|1H-z wherein at least one but not more than two Xs is hydroxyand the remaining non hydroxy Xs are chloro at a reaction temperature offrom room temperature to reflux temperature inclusive, the reactantsbeing reacted in proportions within the molar ranges of about 0.1-0.3mole of the nitrogen heterocyclic compourid, about 0.5-1.5 mole of theamine having at least two functional groups, about 1.0-3.0 moles of theformaldehyde, and about 0.5-1.5 mole of the epihalohydrin or glycerolchlorohydrin.

21. The bath of claim 20 wherein the amine having at least twofunctional groups is monoethanolamine.

22. The bath of claim 21 wherein the epihalohydrin is epichlorohydrin.

23. The bath of claim 22 wherein the bath is a low cyanide content bathhaving a total cyanide content of up to 2.0

oz./gal. and the nitrogen heterocyclic compound is of the fornitrogenheterocyclic compound selected from the group conmula sisting of thoseof the formulae wherein R is hydrogen, methyl, chloro, bromo, amino,cyano, /N vinyl, hydroxypropyl or COOM wherein M is hydrogen or ahydrophilic cation and R is hydrogen or amino with the N proviso thatwhen R is amino R is methyl. y

24. A method for the electrodeposition of bright zinc which compriseselectrodepositing the zinc from an aqueous alkaline and a quinolinewherein R is hydrogen, methyl, chloro, zinc eiectrodepositing bathcomprising an aqueous alkaline bromo, amino, cyano, vinyl, hydroxypropylor -COOM solution containing a source of zinc ions and an effectiveWhereinMis hydrogen orahydrophilic cation, R is hydrogen amount,sufficient to yield a bright zinc electrodeposit, of a or amino with theproviso that when R, is amino R is methyl, bath-soluble reaction productobtained by the reaction of a and R2 i hydrogen, methyl or -COOM whereinM is nitrogen heterocyclic compound with an acyclic amine havinghydrogen or a hydrophilic cation with an acyclic amin h i at least twofunctional groups, formaldehyde, and an at least two un ti nal groups,formaldehyde, and an epihalohydrin wherein the'halogen atom is chloro orbromo or pihalohydrin 0f the formula a glycerol chlorohydrin at areaction temperature of from room temperature to reflux temperatureinclusive.

25. The method of claim 24 wherein the epihalohydrin is 25 ClIP-CIICIIqXepichlorohydrin, and the bath-soluble reaction product is obtained byslowly adding an aqueous formaldehyde solution to a mixture of the aminehaving at least two functional groups, z gzag}: X is chloro or bromo ora glycerol chlorohydnn of the the nitrogen heterocyclic compound and anaqueous diluent while agitating the mixture, slowly adding theepichlorohydrin F E to the thus-obtained mixture while agitating themixture X X X whereby exothermic heat is liberated during the i.

epichlorohydrin addition with an attendant rise in temperawherein atleast one but not more than two X's is hydroxy and ture of the mixtureto about its reflux temperature, and refluxthe remaining non hydroxy Xsare chloro at a reaction teming the resulting mixture for a period of atleast about 20 3 5 perature of from room temperature to refluxtemperature inminutes clusive, the reactants being reacted inproportions within the 26. A method for the electrodeposition of brightzinc which molar ranges of about 0.1-0.3 mole of the nitrogenheterocomprises electrodepositing the zinc from an aqueous alkalineCyclic compound, about 0.5-1.5 mole of the amine having at zincelectrodepositing bath comprising an aqueous alkaline least twofunctional groups, about 1.0-3.0 moles of the forsolution containing asource of zinc ions and an effective 40 maldehyde, and about 0.5-l.5mole of the epihalohydrin or amount, sufficient to yield a bright zincelectrodeposit, of a glycerol chlorohydrin. bath-soluble reactionproduct obtained by the reaction of a Patent No. 3 655 534 Dated 1- 11 I1'q 72 Inventor(s) Marcis M. Kamne It is certified that error appears inthe above-identified patent. and that said Letters Patent are herebycorrected as shown below:

Column 3', line 46, "the" (second occurrence) should read --that--. InTABLE 1, wherever recited, "F, Br" should read ..--F Br--; whereverrecited, "V, Br" should read --V Br--; Test Run Number 18, "CH -CH -CH-CH" should read --CH -CH -CH -QH- Column 10, line 47, "ml." (secondocurrenoe) should be deleted.

Signed and sealed this 28th day of November 1972.

(SEAL) Attest:

. EDWARD M.FLET 1HER ,JR. I ROBERT GOT'I'S CHALK Attestlng Of-flcerCommissioner of Patents

2. The bath of claim 1 wherein the bath is a low cyanide content bathhaving a total cyanide content of up to 2.0 oz./gal. and wherein thenitrogen heterocyclic compound is of the formula wherein R is hydrogen,methyl, chloro, bromo, amino, cyano, vinyl, hydroxypropyl or -COOMwherein M is hydrogen or a hydrophilic cation and R1 is hydrogen oramino with the proviso that when R1 is amino R is methyl.
 3. The bath ofclaim 2 wherein the nitrogen heterocyclic compound is a picoline.
 4. Thebath of claim 3 wherein the picoline is gamma -picoline.
 5. The bath ofclaim 4 wherein an additional reactant is reacted with the otherreactants to form the bath-soluble reaction product, said additionalreactant being an aromatic amine of the formula wherein R is -H, -NH2 or-OH.
 6. The bath of claim 5 wherein the R is -NH2.
 7. The bath of claim2 wherein the nitrogen heterocyclic compound is a pyridinemonocarboxylic acid.
 8. The bath of claim 7 wherein the pyridinecarboxylic acid is nicotinic acid.
 9. The bath of claim 2 wherein thenitrogen heterocyclic compound is 4-picolylamine.
 10. The bath of claim2 wherein the nitrogen heterocyclic compound is 2-chloropyridine. 11.The bath of claim 2 wherein the nitrogen heterocyclic compound is4-vinylpyridine.
 12. The bath of claim 1 wherein the bath-solublereaction product is obtained by the reaction of the nitrogenheterocyclic compound with the amine having at least two functionalgroups, formaldehyde, and the epihalohydrin.
 13. The bath of claim 12wherein the epihalohydrin is epichlorohydrin and the bath-solublereaction product is obtained by slowly adding an aqueous formaldehydesolution to a mixture of the amine having at least two functionalgroups, the nitrogen heterocyclic compound and an aqueous diluent whileagitating the mixture, slowly adding the epichlorohydrin to thethus-obtained mixture while agitating the mixture whereby exothermicheat is liberated during the epichlorohydrin addition with an attendantrise in temperature of the mixture to about its reflux temperature, andrefluxing the resulting mixture for a period of at least about 20minutes.
 14. The bath of claim 1 wherein the nitrogen heterocycliccompound is a quinoline.
 15. The bath of claim 14 wherein the quinolineis isoquinoline.
 16. The bath of claim 1 wherein the bath is free ofcyanide, the nitrogen heterocyclic compound reactant is selected fromthe groups consisting of Alpha -, Beta - and gamma -picolines, nicotinicacid, vinylpyridines, halopyridines wherein the halogen is chloro orbromo, picolylamines, methylpyrazines and quinolines; and the aminereactant having at least two functional groups is selected from thegroups consisting of mono-, di- and triethanolamine,hexamethylenediamine, hexamethylenetetramine, ethylenediamine,diethylenetriamine and tetraethylenepentamine.
 17. The non-cyanide bathof claim 16 wherein the nitrogen heterocyclic compound is selected fromthe group consisting of gamma -picoline, nicotinic acid,4-vinylpyridine, 2-chloropyridine, 4-picolylamine, 2-methylpyrazine andisoquinoline.
 18. The bath of claim 1 wherein the nitrogen heterocycliccompound is 2-methyl pyrazine.
 19. The bath of claim 1 wherein thenitrogen heterocyclic compound is gamma -picoline and 2-methylpyrazine.20. An aqueous alkaline zinc electrodepositing bath comprising anaqueous alkaline solution containing a source of zinc ions and aneffective amount, sufficient to yield a bright zinc electrodeposit, of abath-soluble reaction product obtained by the reaction of a nitrogenheterocyclic compound selected from the group consisting of those of theformulae:
 21. The bath of claim 20 wherein the amine having at least twofunctional groups is monoethanolamine.
 22. The bath of claim 21 whereinthe epihalohydrin is epichlorohydrin.
 23. The bath of claim 22 whereinthe bath is a low cyanide content bath having a total cyanide content ofup to 2.0 oz./gal. and the nitrogen heterocyclic compound is of theformula wherein R is hydrogen, methyl, chloro, bromo, amino, cyano,vinyl, hydroxypropyl or -COOM wherein M is hydrogen or a hydrophiliccation and R1 is hydrogen or amino with the proviso that when R1 isamino R is methyl.
 24. A method for the electrodeposition of bright zincwhich comprises electrodepositing the zinc from an aqueous alkaline zincelectrodepositing bath comprising an aqueous alkaline solutioncontaining a source of zinc ions and an effective amount, sufficient toyield a bright zinc electrodeposit, of a bath-soluble reaction productobtained by the reaction of a nitrogen heterocyclic compound with anacyclic amine having at least two functional groups, formaldehyde, andan epihalohydrin wherein the halogen atom is chloro or bromo or aglycerol chlorohydrin at a reaction temperature of from room temperatureto reflux temperature inclusive.
 25. The method of claim 24 wherein theepihalohydrin is epichlorohydrin, and the bath-soluble reaction productis obtained by slowly adding an aqueous formaldehyde solution to amixture of the amine having at least two functional groups, the nitrogenheterocyclic compound and an aqueous diluent while agitating themixture, slowly adding the epichlorohydrin to the thus-obtained mixturewhile agitating the mixture whereby exothermic heat is liberated duringthe epichlorohydrin addition with an attendant rise in temperature ofthe mixture to about its reflux temperature, and refluxing the resultingmixture for a period of at least about 20 minutes.
 26. A method for theelectrodeposition of bright zinc which comprises electrodepositing thezinc from an aqueous alkaline zinc electrodepositing bath comprising anaqueous alkaline solution containing a source of zinc ions and aneffective amount, sufficient to yield a bright zinc electrodeposit, of abath-soluble reaction product obtained by the reaction of a nitrogenheterocyclic compound selected from the group consisting of those of theformulae